This invention relates to irrigation, and, more particularly, to agricultural irrigation using a movable forward roll wheel line.
Agricultural irrigation is used to ensure a proper water supply to crops which would otherwise receive insufficient water. Water is, in some cases, supplied by flooding or trenches in the ground, and, in other cases, supplied by mechanized irrigation systems. There are numerous types of mechanized agricultural irrigation systems, and one of these, the wheel line and preferably the forward roll wheel line, is the field of application of the present invention.
In a typical forward roll wheel line, a plenum pipe having orifices therein is supported from a number of drive wheels. The plenum pipe is straight and typically from ⅛ to ¼ mile long. A gasoline engine is connected through a gear box to the plenum pipe, which serves as a drive shaft to wheels spaced apart along the plenum pipe. The gasoline engine is operated to turn the plenum pipe and the drive wheels, so that the irrigation source is moved laterally from station-to-station across a field. One end of the plenum pipe is connected to a water source, and irrigation is commenced. After a sufficient period of irrigation, the moving process is repeated. In each move, the plenum pipe is translated a distance such that complete irrigation coverage of the field is achieved after a series of moves. After irrigation at each station is complete, the operator turns off the water source, allows the water to drain from the plenum pipe and the wheel line, disconnects the water source from the wheel line, moves the forward roll wheel line to the next irrigation station, connects the water source, and begins irrigation at that station.
The forward roll wheel line is not to be confused with the linear irrigation line and the center-pivot irrigation line. The linear irrigation line moves linearly but continuously across a field. The center-pivot irrigation line rotates continuously about a center pivot. In each case the movement is continuous, rather than discontinuous as in the case of the forward roll wheel line. Both the linear irrigation line and the center-pivot irrigation line are full of water while moving. Consequently, each requires a much larger drive and support structure than the forward roll wheel line, and each is typically 3-4 times as expensive as the forward roll wheel line. The present invention may be used with linear and center pivot irrigation lines, but it is far less economically advantageous when used with these other line systems.
While the forward roll wheel line is operable and widely used, the inventors have recognized that existing forward roll wheel lines have some significant drawbacks. They may cause substantial environmental pollution and may be dangerous. They require substantial operator attention. There is, accordingly, a need for an improved agricultural forward roll wheel line. The present invention fulfills this need, and further provides related advantages.